The feasibility of identifying, localizing, and quantifying myocardial ischemia, infarction or scarring by changes in left ventricular wall motion and thickening will be assessed in man and animals. Real-time two-dimensional phased array echocardiography in conjunction with an echocardiographic contouring system developed in the parent grant are the techniques to be employed. In dogs, we will assess the accuracy of volume determined in the in-situ left ventricle by correlation with multiple implanted endocardial markers visualized simultaneously by two-dimensional echocardiography and biplane cineangiography. In the in-situ canine heart the association between specific abnormalities of wall motion and thickening, and myocardial infarction, risk region, and regional coronary blood flow will be defined. We will explore the possibility of predicting myocardial infarct size in-situ in canine ventricles subjected to chronic infarction, and in man. In addition, serial studies on patients who have undergone regional expansion of acute myocardial infarction will characterize the clinical course and sequelae, including the relationship to the pathophysiology of left ventricular aneurysm formation. We will continue the development of two-dimensional exercise echocardiographic techniques for the detection of regional wall motion abnormalities during ischemia. We will undertake quantitative evaluation of regional left ventricular thickening in patients with chronic ischemic heart disease by two-dimensional echocardiography, correlating angiographic wall motion abnormalities with abnormalities of thickening determined by the two-dimensional echo contour system. We will implement an ultrasonic transducer location system designed to permit accurate localization of an echocardiographic cross-section with regard to the long axis of the heart, as an essential step for accurate three-dimensional reconstruction of cardiac motion from a set of cross-sectional views.